(HLNtv.com) -- Kendrick Johnson's parents spoke out on HLN's "Nancy Grace" on Thursday, saying that they are "happy" that a federal prosecutor is launching a formal review of the facts surrounding their son's death.

Kenneth Johnson, Kendrick's father, said the family is "going to sit back and wait for everything to come out" related to his son's final moments.

The family's reaction came just hours after U.S. Attorney Michael Moore announced Thursday that federal authorities will investigate Kendrick Johnson's death. The 17-year-old's body was found inside a rolled-up gym mat at Lowndes High School in Valdosta, Ga., on Jan. 11.

Photos obtained by CNN show that Kendrick Johnson's face was bloated and that blood, some of it having spilled on the floor, had soaked his dreadlocks. Yet the Lowndes County Sheriff's Office said foul play was not suspected.

Kenneth Johnson told HLN that he believes the investigation was botched from the start.

"When I went to view Kendrick's body two days later, you could clearly see that something had happened to Kendrick," he said. "You could see that he was in some kind of altercation."

An autopsy by state medical examiners concluded that the death was an accidental result of positional asphyxiation after Kendrick got stuck in the mat. However, an independent examination by a pathologist hired by the family found injuries to his neck and "unexplained, apparent non-accidental, blunt force trauma."

Moore, the U.S. attorney for the Middle District of Georgia, said in a statement that "a sufficient basis exists" for his office to conduct a review of the case.

Kendrick's mother, Jacquelyn Johnson, said she hoped the new investigation would lead to answers.

"I just want to know what happened to Kendrick Johnson," she said.

"We're just going to continue to push forward like we've been doing," Kenneth Johnson added.

Attorneys for the couple say local authorities stonewalled them as they tried to find out what happened. They also say there may be a cover-up to protect whoever was responsible for his death.

Newly unsealed surveillance video from the school could help, but Johnson family attorney Benjamin Crump said they were still waiting to review more than 1,900 hours of video.

"That's but one step to solve this unfortunately real-life murder mystery," Crump said.

Chevene King Jr., another attorney working with the Johnsons, told HLN he believes some people in the community may be afraid to come forward with information about the case.

Attorneys for the sheriff's office and the school said Thursday that they will cooperate fully with the federal prosecutor's investigation.